Archived

Avalanche Forecast

Dec 16th, 2016–Dec 17th, 2016

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Kootenay Boundary.

Fresh and touchy wind slabs are building in unusual places. Use caution as you transition into exposed terrain.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

A mix of sun and cloud for Saturday with moderate northwesterly winds and alpine temperatures around -10. Sunday should be mainly cloudy with flurries bringing around 5 cm of fresh snow by the afternoon. Ridgetop winds are expected to increase to moderate to strong westerlies and alpine temperatures around -10. Expect to wake up Monday morning with 5-10 cm of fresh snow in the mountains with an additional 5-10 cm throughout the day all falling under strong southwesterly winds. Temperatures are expected to warm considerably, but freezing levels should remain in valley bottoms

Avalanche Summary

No new avalanches were reported on Wednesday or Thursday. Reports from Tuesday are limited to natural and rider-triggered sluffs up to Size 1.5. Reports from Monday include sensitive ridgetop wind slabs with numerous Size 1's with ski cuts. Elsewhere, explosives control produced limited results with a few Size 2 slabs that likely ran on the late November rain crust.

Snowpack Summary

Around 30cm of faceted powder overlies the facets and surface hoar that was buried last weekend. Variable light to moderate winds have loaded immediate leeward features with touchy wind slabs. A widespread crust that was buried in November is typically down 80-100cm. Recent tests show this persistent weakness has the propensity to propagate large avalanches if triggered, from thin rocky areas, for instance.

Avalanche Problems

Wind Slabs

Fresh wind slabs on the downwind side of ridge crests and terrain features are highly sensitive to human triggers. Expect to find these deep pillows of wind-transported snow in unusual places thanks to recent northerly winds.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.On steep slopes, pull over periodically or cut into a new line to manage sluffing.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2